Multi-channel optical signals are typically multiplexed at a source with an optical multiplexer (MUX) for transmission to a destination on a common optical transmission line. Prior to the transmission being received by the destination, an optical demultiplexer (DMUX) demultiplexes the transmission back to the multi-channel optical signals. Prior to multiplexing the multi-channel signals at the transmission source, a variable optical attenuator (VOA) may be used for each channel to regulate or attenuate the optical power of each channel. Additionally, a VOA may be used for each channel after being demultiplexed at the destination to regulate or attenuate the optical power of each channel.
To provide system safety, each VOA can be typically set to its maximum attenuation value or a certain configurable attenuation value in case of electrical power failure. This feature is called Automatic VOA Shutdown (AVS). The AVS feature is typically implemented in each VOA. However, because high attenuation is required for each VOA in a power-off condition, high electrical power has to be provided to sustain regular attenuation during power-on conditions. Supplying high electrical power to each VOA can cause heat generation in each VOA that can lead to thermal management, which may become a significant problem when a high number of optical channels are present.